#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

static char *ngx_http_mymodule(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static ngx_int_t ngx_http_mymodule_handler(ngx_http_request_t *r);

static ngx_command_t ngx_http_mymodule_commands[] = {
    {
        ngx_string("mymodule"),
        NGX_HTTP_LOC_CONF | NGX_CONF_NOARGS,
        ngx_http_mymodule,
        0,
        0,
        NULL
    },
    ngx_null_command
};

static ngx_http_module_t ngx_http_mymodule_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};

ngx_module_t ngx_http_mymodule_module = {
    NGX_MODULE_V1,
    &ngx_http_mymodule_module_ctx,         /* module context */
    ngx_http_mymodule_commands,            /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

static ngx_int_t ngx_http_mymodule_handler(ngx_http_request_t *r)
{
    ngx_str_t type = ngx_string("text/plain");
    ngx_str_t response = ngx_string("Hello from MyModule!");

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = response.len;
    r->headers_out.content_type = type;

    ngx_buf_t *b;
    ngx_chain_t out;

    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    out.buf = b;
    out.next = NULL;

    b->pos = response.data;
    b->last = response.data + response.len;
    b->memory = 1;
    b->last_buf = 1;

    ngx_http_send_header(r);
    return ngx_http_output_filter(r, &out);
}

static char *ngx_http_mymodule(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_core_loc_conf_t *clcf;

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_http_mymodule_handler;

    return NGX_CONF_OK;
}
